text: /* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * dlmconvert.c
   *
   * underlying calls for lock conversion
   *
   * Copyright (C) 2004 Oracle.  All rights reserved.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public
   * License as published by the Free Software Foundation; either
   * version 2 of the License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public
   * License along with this program; if not, write to the
   * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   * Boston, MA 021110-1307, USA.
   *
   */
  
  
  #include <linux/module.h>
  #include <linux/fs.h>
  #include <linux/types.h>
  #include <linux/highmem.h>
  #include <linux/init.h>
  #include <linux/sysctl.h>
  #include <linux/random.h>
  #include <linux/blkdev.h>
  #include <linux/socket.h>
  #include <linux/inet.h>
  #include <linux/spinlock.h>
  
  
  #include "cluster/heartbeat.h"
  #include "cluster/nodemanager.h"
  #include "cluster/tcp.h"
  
  #include "dlmapi.h"
  #include "dlmcommon.h"
  
  #include "dlmconvert.h"
  
  #define MLOG_MASK_PREFIX ML_DLM
  #include "cluster/masklog.h"
  
  /* NOTE: __dlmconvert_master is the only function in here that
   * needs a spinlock held on entry (res->spinlock) and it is the
   * only one that holds a lock on exit (res->spinlock).
   * All other functions in here need no locks and drop all of
   * the locks that they acquire. */
  static enum dlm_status __dlmconvert_master(struct dlm_ctxt *dlm,
  					   struct dlm_lock_resource *res,
  					   struct dlm_lock *lock, int flags,
  					   int type, int *call_ast,
  					   int *kick_thread);
  static enum dlm_status dlm_send_remote_convert_request(struct dlm_ctxt *dlm,
  					   struct dlm_lock_resource *res,
  					   struct dlm_lock *lock, int flags, int type);
  
  /*
   * this is only called directly by dlmlock(), and only when the
   * local node is the owner of the lockres
   * locking:
   *   caller needs:  none
   *   taken:         takes and drops res->spinlock
   *   held on exit:  none
   * returns: see __dlmconvert_master
   */
  enum dlm_status dlmconvert_master(struct dlm_ctxt *dlm,
  				  struct dlm_lock_resource *res,
  				  struct dlm_lock *lock, int flags, int type)
  {
  	int call_ast = 0, kick_thread = 0;
  	enum dlm_status status;
  
  	spin_lock(&res->spinlock);
  	/* we are not in a network handler, this is fine */
  	__dlm_wait_on_lockres(res);
  	__dlm_lockres_reserve_ast(res);
  	res->state |= DLM_LOCK_RES_IN_PROGRESS;
  
  	status = __dlmconvert_master(dlm, res, lock, flags, type,
  				     &call_ast, &kick_thread);
  
  	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
  	spin_unlock(&res->spinlock);
  	wake_up(&res->wq);
  	if (status != DLM_NORMAL && status != DLM_NOTQUEUED)
  		dlm_error(status);
  
  	/* either queue the ast or release it */
  	if (call_ast)
  		dlm_queue_ast(dlm, lock);
  	else
  		dlm_lockres_release_ast(dlm, res);
  
  	if (kick_thread)
  		dlm_kick_thread(dlm, res);
  
  	return status;
  }
  
  /* performs lock conversion at the lockres master site
   * locking:
   *   caller needs:  res->spinlock
   *   taken:         takes and drops lock->spinlock
   *   held on exit:  res->spinlock
   * returns: DLM_NORMAL, DLM_NOTQUEUED, DLM_DENIED
   *   call_ast: whether ast should be called for this lock
   *   kick_thread: whether dlm_kick_thread should be called
   */
  static enum dlm_status __dlmconvert_master(struct dlm_ctxt *dlm,
  					   struct dlm_lock_resource *res,
  					   struct dlm_lock *lock, int flags,
  					   int type, int *call_ast,
  					   int *kick_thread)
  {
  	enum dlm_status status = DLM_NORMAL;
  	struct dlm_lock *tmplock=NULL;
  
  	assert_spin_locked(&res->spinlock);
  
  	mlog(0, "type=%d, convert_type=%d, new convert_type=%d\n",
  	     lock->ml.type, lock->ml.convert_type, type);
  
  	spin_lock(&lock->spinlock);
  
  	/* already converting? */
  	if (lock->ml.convert_type != LKM_IVMODE) {
  		mlog(ML_ERROR, "attempted to convert a lock with a lock "
  		     "conversion pending\n");
  		status = DLM_DENIED;
  		goto unlock_exit;
  	}
  
  	/* must be on grant queue to convert */
  	if (!dlm_lock_on_list(&res->granted, lock)) {
  		mlog(ML_ERROR, "attempted to convert a lock not on grant "
  		     "queue\n");
  		status = DLM_DENIED;
  		goto unlock_exit;
  	}
  
  	if (flags & LKM_VALBLK) {
  		switch (lock->ml.type) {
  			case LKM_EXMODE:
  				/* EX + LKM_VALBLK + convert == set lvb */
  				mlog(0, "will set lvb: converting %s->%s\n",
  				     dlm_lock_mode_name(lock->ml.type),
  				     dlm_lock_mode_name(type));
  				lock->lksb->flags |= DLM_LKSB_PUT_LVB;
  				break;
  			case LKM_PRMODE:
  			case LKM_NLMODE:
  				/* refetch if new level is not NL */
  				if (type > LKM_NLMODE) {
  					mlog(0, "will fetch new value into "
  					     "lvb: converting %s->%s\n",
  					     dlm_lock_mode_name(lock->ml.type),
  					     dlm_lock_mode_name(type));
  					lock->lksb->flags |= DLM_LKSB_GET_LVB;
  				} else {
  					mlog(0, "will NOT fetch new value "
  					     "into lvb: converting %s->%s\n",
  					     dlm_lock_mode_name(lock->ml.type),
  					     dlm_lock_mode_name(type));
  					flags &= ~(LKM_VALBLK);
  				}
  				break;
  		}
  	}
  
  
  	/* in-place downconvert? */
  	if (type <= lock->ml.type)
  		goto grant;
  
  	/* upconvert from here on */
  	status = DLM_NORMAL;
  	list_for_each_entry(tmplock, &res->granted, list) {
  		if (tmplock == lock)
  			continue;
  		if (!dlm_lock_compatible(tmplock->ml.type, type))
  			goto switch_queues;
  	}
  
  	list_for_each_entry(tmplock, &res->converting, list) {
  		if (!dlm_lock_compatible(tmplock->ml.type, type))
  			goto switch_queues;
  		/* existing conversion requests take precedence */
  		if (!dlm_lock_compatible(tmplock->ml.convert_type, type))
  			goto switch_queues;
  	}
  
  	/* fall thru to grant */
  
  grant:
  	mlog(0, "res %.*s, granting %s lock\n", res->lockname.len,
  	     res->lockname.name, dlm_lock_mode_name(type));
  	/* immediately grant the new lock type */
  	lock->lksb->status = DLM_NORMAL;
  	if (lock->ml.node == dlm->node_num)
  		mlog(0, "doing in-place convert for nonlocal lock\n");
  	lock->ml.type = type;
  	if (lock->lksb->flags & DLM_LKSB_PUT_LVB)
  		memcpy(res->lvb, lock->lksb->lvb, DLM_LVB_LEN);
  
  	/*
  	 * Move the lock to the tail because it may be the only lock which has
  	 * an invalid lvb.
  	 */
  	list_move_tail(&lock->list, &res->granted);
  
  	status = DLM_NORMAL;
  	*call_ast = 1;
  	goto unlock_exit;
  
  switch_queues:
  	if (flags & LKM_NOQUEUE) {
  		mlog(0, "failed to convert NOQUEUE lock %.*s from "
  		     "%d to %d...\n", res->lockname.len, res->lockname.name,
  		     lock->ml.type, type);
  		status = DLM_NOTQUEUED;
  		goto unlock_exit;
  	}
  	mlog(0, "res %.*s, queueing...\n", res->lockname.len,
  	     res->lockname.name);
  
  	lock->ml.convert_type = type;
  	/* do not alter lock refcount.  switching lists. */
  	list_move_tail(&lock->list, &res->converting);
  
  unlock_exit:
  	spin_unlock(&lock->spinlock);
  	if (status == DLM_DENIED) {
  		__dlm_print_one_lock_resource(res);
  	}
  	if (status == DLM_NORMAL)
  		*kick_thread = 1;
  	return status;
  }
  
  void dlm_revert_pending_convert(struct dlm_lock_resource *res,
  				struct dlm_lock *lock)
  {
  	/* do not alter lock refcount.  switching lists. */
  	list_move_tail(&lock->list, &res->granted);
  	lock->ml.convert_type = LKM_IVMODE;
  	lock->lksb->flags &= ~(DLM_LKSB_GET_LVB|DLM_LKSB_PUT_LVB);
  }
  
  /* messages the master site to do lock conversion
   * locking:
   *   caller needs:  none
   *   taken:         takes and drops res->spinlock, uses DLM_LOCK_RES_IN_PROGRESS
   *   held on exit:  none
   * returns: DLM_NORMAL, DLM_RECOVERING, status from remote node
   */
  enum dlm_status dlmconvert_remote(struct dlm_ctxt *dlm,
  				  struct dlm_lock_resource *res,
  				  struct dlm_lock *lock, int flags, int type)
  {
  	enum dlm_status status;
  	u8 old_owner = res->owner;
  
  	mlog(0, "type=%d, convert_type=%d, busy=%d\n", lock->ml.type,
  	     lock->ml.convert_type, res->state & DLM_LOCK_RES_IN_PROGRESS);
  
  	spin_lock(&res->spinlock);
  	if (res->state & DLM_LOCK_RES_RECOVERING) {
  		mlog(0, "bailing out early since res is RECOVERING "
  		     "on secondary queue\n");
  		/* __dlm_print_one_lock_resource(res); */
  		status = DLM_RECOVERING;
  		goto bail;
  	}
  	/* will exit this call with spinlock held */
  	__dlm_wait_on_lockres(res);
  
  	if (lock->ml.convert_type != LKM_IVMODE) {
  		__dlm_print_one_lock_resource(res);
  		mlog(ML_ERROR, "converting a remote lock that is already "
  		     "converting! (cookie=%u:%llu, conv=%d)\n",
  		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
  		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
  		     lock->ml.convert_type);
  		status = DLM_DENIED;
  		goto bail;
  	}
  
  	if (lock->ml.type == type && lock->ml.convert_type == LKM_IVMODE) {
  		mlog(0, "last convert request returned DLM_RECOVERING, but "
  		     "owner has already queued and sent ast to me. res %.*s, "
  		     "(cookie=%u:%llu, type=%d, conv=%d)\n",
  		     res->lockname.len, res->lockname.name,
  		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
  		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
  		     lock->ml.type, lock->ml.convert_type);
  		status = DLM_NORMAL;
  		goto bail;
  	}
  
  	res->state |= DLM_LOCK_RES_IN_PROGRESS;
  	/* move lock to local convert queue */
  	/* do not alter lock refcount.  switching lists. */
  	list_move_tail(&lock->list, &res->converting);
  	lock->convert_pending = 1;
  	lock->ml.convert_type = type;
  
  	if (flags & LKM_VALBLK) {
  		if (lock->ml.type == LKM_EXMODE) {
  			flags |= LKM_PUT_LVB;
  			lock->lksb->flags |= DLM_LKSB_PUT_LVB;
  		} else {
  			if (lock->ml.convert_type == LKM_NLMODE)
  				flags &= ~LKM_VALBLK;
  			else {
  				flags |= LKM_GET_LVB;
  				lock->lksb->flags |= DLM_LKSB_GET_LVB;
  			}
  		}
  	}
  	spin_unlock(&res->spinlock);
  
  	/* no locks held here.
  	 * need to wait for a reply as to whether it got queued or not. */
  	status = dlm_send_remote_convert_request(dlm, res, lock, flags, type);
  
  	spin_lock(&res->spinlock);
  	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
  	lock->convert_pending = 0;
  	/* if it failed, move it back to granted queue.
  	 * if master returns DLM_NORMAL and then down before sending ast,
  	 * it may have already been moved to granted queue, reset to
  	 * DLM_RECOVERING and retry convert */
  	if (status != DLM_NORMAL) {
  		if (status != DLM_NOTQUEUED)
  			dlm_error(status);
  		dlm_revert_pending_convert(res, lock);
  	} else if ((res->state & DLM_LOCK_RES_RECOVERING) ||
  			(old_owner != res->owner)) {
  		mlog(0, "res %.*s is in recovering or has been recovered.\n",
  				res->lockname.len, res->lockname.name);
  		status = DLM_RECOVERING;
  	}
  bail:
  	spin_unlock(&res->spinlock);
  
  	/* TODO: should this be a wake_one? */
  	/* wake up any IN_PROGRESS waiters */
  	wake_up(&res->wq);
  
  	return status;
  }
  
  /* sends DLM_CONVERT_LOCK_MSG to master site
   * locking:
   *   caller needs:  none
   *   taken:         none
   *   held on exit:  none
   * returns: DLM_NOLOCKMGR, status from remote node
   */
  static enum dlm_status dlm_send_remote_convert_request(struct dlm_ctxt *dlm,
  					   struct dlm_lock_resource *res,
  					   struct dlm_lock *lock, int flags, int type)
  {
  	struct dlm_convert_lock convert;
  	int tmpret;
  	enum dlm_status ret;
  	int status = 0;
  	struct kvec vec[2];
  	size_t veclen = 1;
  
  	mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);
  
  	memset(&convert, 0, sizeof(struct dlm_convert_lock));
  	convert.node_idx = dlm->node_num;
  	convert.requested_type = type;
  	convert.cookie = lock->ml.cookie;
  	convert.namelen = res->lockname.len;
  	convert.flags = cpu_to_be32(flags);
  	memcpy(convert.name, res->lockname.name, convert.namelen);
  
  	vec[0].iov_len = sizeof(struct dlm_convert_lock);
  	vec[0].iov_base = &convert;
  
  	if (flags & LKM_PUT_LVB) {
  		/* extra data to send if we are updating lvb */
  		vec[1].iov_len = DLM_LVB_LEN;
  		vec[1].iov_base = lock->lksb->lvb;
  		veclen++;
  	}
  
  	tmpret = o2net_send_message_vec(DLM_CONVERT_LOCK_MSG, dlm->key,
  					vec, veclen, res->owner, &status);
  	if (tmpret >= 0) {
  		// successfully sent and received
  		ret = status;  // this is already a dlm_status
  		if (ret == DLM_RECOVERING) {
  			mlog(0, "node %u returned DLM_RECOVERING from convert "
  			     "message!\n", res->owner);
  		} else if (ret == DLM_MIGRATING) {
  			mlog(0, "node %u returned DLM_MIGRATING from convert "
  			     "message!\n", res->owner);
  		} else if (ret == DLM_FORWARD) {
  			mlog(0, "node %u returned DLM_FORWARD from convert "
  			     "message!\n", res->owner);
  		} else if (ret != DLM_NORMAL && ret != DLM_NOTQUEUED)
  			dlm_error(ret);
  	} else {
  		mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
  		     "node %u\n", tmpret, DLM_CONVERT_LOCK_MSG, dlm->key,
  		     res->owner);
  		if (dlm_is_host_down(tmpret)) {
  			/* instead of logging the same network error over
  			 * and over, sleep here and wait for the heartbeat
  			 * to notice the node is dead.  times out after 5s. */
  			dlm_wait_for_node_death(dlm, res->owner,
  						DLM_NODE_DEATH_WAIT_MAX);
  			ret = DLM_RECOVERING;
  			mlog(0, "node %u died so returning DLM_RECOVERING "
  			     "from convert message!\n", res->owner);
  		} else {
  			ret = dlm_err_to_dlm_status(tmpret);
  		}
  	}
  
  	return ret;
  }
  
  /* handler for DLM_CONVERT_LOCK_MSG on master site
   * locking:
   *   caller needs:  none
   *   taken:         takes and drop res->spinlock
   *   held on exit:  none
   * returns: DLM_NORMAL, DLM_IVLOCKID, DLM_BADARGS,
   *          status from __dlmconvert_master
   */
  int dlm_convert_lock_handler(struct o2net_msg *msg, u32 len, void *data,
  			     void **ret_data)
  {
  	struct dlm_ctxt *dlm = data;
  	struct dlm_convert_lock *cnv = (struct dlm_convert_lock *)msg->buf;
  	struct dlm_lock_resource *res = NULL;
  	struct dlm_lock *lock = NULL;
  	struct dlm_lock *tmp_lock;
  	struct dlm_lockstatus *lksb;
  	enum dlm_status status = DLM_NORMAL;
  	u32 flags;
  	int call_ast = 0, kick_thread = 0, ast_reserved = 0, wake = 0;
  
  	if (!dlm_grab(dlm)) {
  		dlm_error(DLM_REJECTED);
  		return DLM_REJECTED;
  	}
  
  	mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
  			"Domain %s not fully joined!\n", dlm->name);
  
  	if (cnv->namelen > DLM_LOCKID_NAME_MAX) {
  		status = DLM_IVBUFLEN;
  		dlm_error(status);
  		goto leave;
  	}
  
  	flags = be32_to_cpu(cnv->flags);
  
  	if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
  	     (LKM_PUT_LVB|LKM_GET_LVB)) {
  		mlog(ML_ERROR, "both PUT and GET lvb specified\n");
  		status = DLM_BADARGS;
  		goto leave;
  	}
  
  	mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
  	     (flags & LKM_GET_LVB ? "get lvb" : "none"));
  
  	status = DLM_IVLOCKID;
  	res = dlm_lookup_lockres(dlm, cnv->name, cnv->namelen);
  	if (!res) {
  		dlm_error(status);
  		goto leave;
  	}
  
  	spin_lock(&res->spinlock);
  	status = __dlm_lockres_state_to_status(res);
  	if (status != DLM_NORMAL) {
  		spin_unlock(&res->spinlock);
  		dlm_error(status);
  		goto leave;
  	}
  	list_for_each_entry(tmp_lock, &res->granted, list) {
  		if (tmp_lock->ml.cookie == cnv->cookie &&
  		    tmp_lock->ml.node == cnv->node_idx) {
  			lock = tmp_lock;
  			dlm_lock_get(lock);
  			break;
  		}
  	}
  	spin_unlock(&res->spinlock);
  	if (!lock) {
  		status = DLM_IVLOCKID;
  		mlog(ML_ERROR, "did not find lock to convert on grant queue! "
  			       "cookie=%u:%llu\n",
  		     dlm_get_lock_cookie_node(be64_to_cpu(cnv->cookie)),
  		     dlm_get_lock_cookie_seq(be64_to_cpu(cnv->cookie)));
  		dlm_print_one_lock_resource(res);
  		goto leave;
  	}
  
  	/* found the lock */
  	lksb = lock->lksb;
  
  	/* see if caller needed to get/put lvb */
  	if (flags & LKM_PUT_LVB) {
  		BUG_ON(lksb->flags & (DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));
  		lksb->flags |= DLM_LKSB_PUT_LVB;
  		memcpy(&lksb->lvb[0], &cnv->lvb[0], DLM_LVB_LEN);
  	} else if (flags & LKM_GET_LVB) {
  		BUG_ON(lksb->flags & (DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));
  		lksb->flags |= DLM_LKSB_GET_LVB;
  	}
  
  	spin_lock(&res->spinlock);
  	status = __dlm_lockres_state_to_status(res);
  	if (status == DLM_NORMAL) {
  		__dlm_lockres_reserve_ast(res);
  		ast_reserved = 1;
  		res->state |= DLM_LOCK_RES_IN_PROGRESS;
  		status = __dlmconvert_master(dlm, res, lock, flags,
  					     cnv->requested_type,
  					     &call_ast, &kick_thread);
  		res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
  		wake = 1;
  	}
  	spin_unlock(&res->spinlock);
  	if (wake)
  		wake_up(&res->wq);
  
  	if (status != DLM_NORMAL) {
  		if (status != DLM_NOTQUEUED)
  			dlm_error(status);
  		lksb->flags &= ~(DLM_LKSB_GET_LVB|DLM_LKSB_PUT_LVB);
  	}
  
  leave:
  	if (lock)
  		dlm_lock_put(lock);
  
  	/* either queue the ast or release it, if reserved */
  	if (call_ast)
  		dlm_queue_ast(dlm, lock);
  	else if (ast_reserved)
  		dlm_lockres_release_ast(dlm, res);
  
  	if (kick_thread)
  		dlm_kick_thread(dlm, res);
  
  	if (res)
  		dlm_lockres_put(res);
  
  	dlm_put(dlm);
  
  	return status;
  }
  